Re: Why two stacks per process?

["Robert P. J. Day" <rpjday@xxxxxxxxxxxxxx>]

On Thu, 24 Apr 2008, sahlot arvind wrote:

> Yes. I agree with Robert. There are two stacks per process. But why
> cannot we just use one stack as I said earlier?

while there may be other reasons, there's one obvious one -- as i
mentioned in my earlier email, the kernel likes to store a small,
pre-process "thread_info" structure at the bottom of the kernel stack.
in short, that per-process stack has to exist the whole time the
process does, since it's actually keeping track of some process
information.  you couldn't do that if you just used the user-space
stack.

rday
--

========================================================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry:
    Have classroom, will lecture.

http://crashcourse.ca                          Waterloo, Ontario, CANADA
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